~wgrant/papyon/master

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# -*- coding: utf-8 -*-
#
# Copyright (C) 2006  Ali Sabil <ali.sabil@gmail.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
#

"""Some missing weak refs"""

from weakref import WeakKeyDictionary
from sets import Set

__all__ = ['WeakSet']

class WeakSet(Set):
    def __init__(self, iterable=None):
        Set.__init__(self)
        self._data = WeakKeyDictionary()
        if iterable is not None:
            self._update(iterable)

    def __hash__(self):
        raise TypeError, "Can't hash a WeakSet."